Troubled forecast for warming Arctic

Ice, walrus numbers shrink

For a second straight year, the Arctic is warming faster than any other place in the world, and walrus populations in the area’s Pacific and Atlantic ocean regions are thinning along with the ice sheets that are critical for their survival, researchers reported.

Overall, the outlook for the frozen top of the world is bleak, according to the annual Arctic Report Card: 2015 Update released by the federal National Oceanic and Atmospheric Administration. Since the turn of the past century, it said, the Arctic’s air temperature has increased by more than 5 degrees because of global warming.

Warmer air and sea temperatures melt ice that in turn expands oceans and causes sea-level rise, which scientists say presents a danger to cities along the entire U.S. Atlantic coast. Walruses and other arctic mammals that give birth on ice sheets are struggling with the change, and fish such as cod and Greenland halibut are swimming north from fishermen and animals that feed on them in pursuit of colder waters.

NOAA chief scientist Richard Spinrad said changes in the Arctic foreshadow others that are likely to spread to the wider world: higher air temperatures, longer hot seasons, abnormal weather spikes and fish fleeing north, only to be replaced by new species swimming from areas south. “The conclusion that comes to my mind is these report cards are trailing indicators of what’s happening in the Arctic. They can turn out to be leading indicators for the rest of the globe,” Spinrad said.

The annual average surface-air temperature over the period of the report, between October 2014 and September 2015, was nearly 2.5 degrees higher than in the time period that scientists use as a baseline to compare temperatures, 1981 to 2010. As a result, Alaska was warmer in fall 2014 and winter this year, when the snowpack that usually melts to replenish rivers and moisten the earth was extremely low.

Lightning strikes on dry land sparked that state’s second-worst wildfire season in its history. According to the NOAA report card, “the 2015 spring melt season provided evidence of earlier snow melt across the Arctic” because of the increased warmth. As of early July, the Arctic melt included more than half the region’s ice sheet for the first time “since the exceptional melt of 2012.” The length of the melt season was up to 40 days longer than that of the average northwestern, northeastern and western regions, the report said.

This year’s findings are largely consistent with dire findings last year. Dozens of scientists from across the world contribute to the report card, including those from Naval Research and the Army Corps of Engineers, the Institute of Marine Research in Norway, Knipovich Polar Research Institute of Marine Fisheries and Oceanography in Russia, and the University of Victoria in Canada.

The report cards’ year-to-year consistency will help scientists establish whether they are watching a weather anomaly in a key part of the world or an established trend. “What you see here is stronger confirmation,” Spinrad said.